Nodejs mysql transaction rollback not working - mysql

Question

I am using Nodejs MySQL and tried to create database level transaction so that I can execute a bunch of statements in a batch and rollback if there is an error in any step. I tried to follow this tutorial.
My database module is:
let mysql = require('mysql')
let keys = require('../config/keys')
let util = require('util')
let pool = mysql.createPool({
connectionLimit: 20,
host: keys.connection.host,
user: keys.connection.user,
password: keys.connection.password,
database: keys.connection.database,
dateStrings: true
// debug:true //Set this to true for verbose debugging. Leaving this to default for now cause it is creating too many messages at my console
})
pool.getConnection((err, connection) => {
if (err) {
if (err.code === 'PROTOCOL_CONNECTION_LOST') {
console.error('Database connection was closed.')
}
if (err.code === 'ER_CON_COUNT_ERROR') {
console.error('Database has too many connections.')
}
if (err.code === 'ECONNREFUSED') {
console.error('Database connection was refused.')
}
}
if (connection) connection.release()
return
})
pool.query = util.promisify(pool.query)
const connection = () => {
return new Promise((resolve, reject) => {
pool.getConnection((err, connection) => {
if (err) reject(err);
console.log("MySQL pool connected: threadId " + connection.threadId);
const query = (sql, binding) => {
return new Promise((resolve, reject) => {
connection.query(sql, binding, (err, result) => {
if (err) reject(err);
resolve(result);
});
});
};
const release = () => {
return new Promise((resolve, reject) => {
if (err) reject(err);
console.log("MySQL pool released: threadId " + connection.threadId);
resolve(connection.release());
});
};
resolve({
query,
release
});
});
});
};
// const query = (sql, binding) => {
// return new Promise((resolve, reject) => {
// pool.query(sql, binding, (err, result, fields) => {
// if (err) reject(err);
// resolve(result);
// });
// });
// };
module.exports = {
pool,
connection
}
In my route, I am trying to use the connection which should allow transaction:
const mysql = require('../../middleware/database')
async function buildCoreSchemas(){
const connection = await mysql.connection();
try{
await connection.query("START TRANSACTION");
await connection.query(`CREATE TABLE adjustreason (
AdjustID int NOT NULL AUTO_INCREMENT,
AdjustReason varchar(100) NOT NULL,
PRIMARY KEY (AdjustID)
)`)
await connection.query(`insert into adjustreason(AdjustReason) values('sdsds')`)
await connection.query(`insert into adjustreason(FAKECOLUMN) values('sdsds')`)
await connection.query("COMMIT");
}
catch(err){
await connection.query("ROLLBACK");
console.log(err)
return false
}
finally {
await connection.release();
}
As you can see I my second insert statement is wrong as there is no column name called FAKE COLUMN. So, the error gets caught and I get the error message in my console:
Unknown column 'FAKECOLUMN' in 'field list
But when I go and look at my database the transaction is not rollbacked because I can see that the first record is still there. What am I doing wrong?

Answer 1

Ciao, try to modify code in this way:
connection.beginTransaction(function(err) {
if (err) { throw err; }
connection.query(`CREATE TABLE adjustreason (
AdjustID int NOT NULL AUTO_INCREMENT,
AdjustReason varchar(100) NOT NULL,
PRIMARY KEY (AdjustID)
)`, function (error, results, fields) {
if (error) {
return connection.rollback(function() {
throw error;
});
}
connection.query(`insert into adjustreason(AdjustReason) values('sdsds')`, function
(error, results, fields) {
if (error) {
return connection.rollback(function() {
throw error;
});
}
connection.query(`insert into adjustreason(FAKECOLUMN) values('sdsds')`, function
(error, results, fields) {
if (error) {
return connection.rollback(function() {
throw error;
});
}
connection.commit(function(err) {
if (err) {
return connection.rollback(function() {
throw err;
});
}
console.log('success!');
});
});
});
});
});
so you call connection.query inside connection.beginTransaction and if one of those query fails, you call connection.rollback. Otherwise connection.commit